Iodine(V) reagents in organic synthesis. Dess-Martin periodinane mediated efficient one-pot oxidation of aldehydes to acyl azides

A mild, efficient and general method for the one-step preparation of acyl azides from aldehydes using Dess-Martin periodinane and sodium azide is described.     

Isolation and characterization of process related impurities of olanzapine using HPLC and ESI-MS/MS

An RP-HPLC method for the simultaneous separation and determination of olanzapine (OLZ) and its process impurities in bulk drugs and pharmaceutical formulations was developed. The separation was accomplished on Inertsil ODS 3V (4.6 mm x 250 mm; particle size 5 microm) column using 0.2 M ammonium acetate (pH = 4.50) and ACN as mobile phase in gradient elution mode. The analytes were monitored by a photo diode array (PDA) detector set at 254 nm and the flow rate was kept at 1.0 mL/min. The chromatographic behavior of all the compounds was examined under variable compositions of different solvents, buffer concentrations, and pH. The method was validated in terms of accuracy, precision, and linearity. Four unknown process impurities observed consistently during the analysis of different batches of OLZ were isolated and characterized by ESI-MS/MS, (1)H NMR, and FT-IR. The proposed RP-HPLC method was successfully applied to the analysis of commercial formulations. The method could be of use not only for rapid and routine evaluation of the quality of OLZ in bulk drug manufacturing units but also for the detection of its impurities in pharmaceutical formulations.     

An efficient total synthesis of (+)-Cladospolide C

The asymmetric synthesis of (+)-Cladospolide C has been achieved in 11 steps with 26% overall yield. Key steps in the sequence involve KAPA-promoted alkyne Zipper reaction, TPP-promoted enyne ester (ynoate) to diene ester (dienoate) isomerization, Sharpless asymmetric dihydroxylation and Yamaguchi macrolactonization.     

Stereoselective total synthesis of (+)-cardiobutanolide and (+)-3-epi-cardiobutanolide from diacetone d-glucose

A chiron approach starting with 3-O-benzyl-1,2-O-isopropylidene-α-d-xylo-pentodialdo-1,4-furanose utilizing a Grignard reaction, Mitsunobu stereoinversion, ethyl diazoacetate addition, and selective reduction of the ketone is employed as a key step for the total synthesis of (+)-cardiobutanolide described; a similar strategy is also reported for the first total synthesis of (+)-3-epi-cardiobutanolide.     

Selectfluor™: A simple and efficient catalyst for the synthesis of substituted coumarins under solvent‐free conditions

Selectfluor? is used as an alternative catalyst to conventional catalysts for the synthesis of substituted coumarins via Pechmann condensation of phenols with β‐ketoesters under solvent‐free conditions at 120 °C. This method of synthesis is simple, cost‐effective, requires short reaction time, solvent‐free and gives good yields.     

Efficient synthesis of benzo[g]-and benzo[h]chromene derivatives by one-pot three-component condensation of aromatic aldehydes with active methylene compounds and naphthols

A convenient procedure is reported for the synthesis of benzo[g]-and benzo[h]chromene derivatives via one-pot three-component condensation of aromatic aldehydes with malononitrile or ethyl cyanoacetate and 1-or 2-naphthol in the presence of 10 mol % of titanium tetrachloride as catalyst. The reactions require no solvent; they are characterized by simple experimental procedure and easy isolation and can be performed on enlarged scale. Published in Russian in Zhurnal Organicheskoi Khimii, 2006, Vol. 42, No. 12, pp. 1824–1826. The text was submitted by the authors in English.     

One-pot synthesis and biological evaluation of novel 4-[3-fluoro-4-(morpholin-4-yl)]phenyl-1H-1,2,3-triazole derivatives as potent antibacterial and anticancer agents

In search of better antibacterial and anticancer agents, a series of novel 4-[3-fluoro-4-(morpholin-4-yl)]phenyl-1H-1,2,3-triazole derivatives were synthesized ( 6a - l and 8a - j ) by using 3-fluoro-4-morpholinoaniline, alkyne, and triflyl azide via an in situ generated 4-(4-azido-2-fluorophenyl)morpholine and evaluated for their antibacterial and anticancer activity in vitro. Antibacterial activity against three G+ bacterial strains and anticancer activity against breast cancer cell line (MCF-7) and cervical carcinoma cell line (HeLa) was evaluated. Among all the tested compounds, 6h , 6i , and 8b exhibited potent antibacterial activity against tested gram-positive bacterial strains. The anticancer activity screening results of 8f , 8h , and 8i exhibited potent cytotoxic activity against two cancer cell lines with IC₅₀ values nearer to the standard drug, doxorubicin. The remaining compounds have shown good to moderate activity against the tested cell lines. On the basis of the results obtained, a structure-activity relationship (SAR) is discussed.     

Solvent‐Specific C―N Bond Formation: Synthesis of Novel Ninhydrin–Creatinine Heterocyclic Condensation Products

Novel ninhydrin–creatinine heterocyclic condensation products ( 3–5 ) were synthesized under different solvent conditions. The compound 2‐(2‐amino‐1‐methyl‐4‐oxo‐4,5‐dihydro‐1H‐imidazol‐5‐yl)‐2‐hydroxy‐1H‐ind‐ene‐1,3(2H)‐dione ( 3 ) was formed by reacting ninhydrin ( 1 ) with creatinine ( 2 ) in the presence of sodium acetate in acetic acid. The same reactants afforded the zwitterionic compound 4 when the reaction was carried out in water, and a novel oxadiazine ring system (product 5 ) was generated when benzene was used as solvent.     

Convenient and Scalable Process for the Preparation of Bupropion Hydrochloride via Efficient Bromination of m-Chloropropiophenone with N-Bromosuccinimide

A convenient, scalable, and commercially viable process for the production of the antidepressant drug bupropion hydrochloride (1) is reported. The process relies upon an improved, large-scale synthesis of the key intermediate, m-chloro-α-bromopropiophenone (4). During process development, bromine was replaced with N-bromosuccinimide (NBS) in the presence of para-toluene sulfonic acid (p-TSA), for the bromination of m-chloropropiophenone (3), in either a very low volume of acetonitrile or under solvent-free conditions, to furnish 4. Intermediate 4 was further reacted with t-butylamine in N-methyl-2-pyrrolidinone (NMP) to afford bupropion free base (5), followed by treatment with a saturated solution of hydrochloric acid in isopropyl alcohol (IPA-HCl) to afford bupropion hydrochloride (1). This improved process provides pure bupropion hydrochloride (1) in good yields and at considerably lower cost than existing processes, and it does not involve the use of hazardous reagents.